1. Technical Field
The present invention relates to a liquid discharging apparatus and a controlling method therefor.
2. Related Art
An ink jet type printer performs printing by discharging ink inside a cavity. When the ink dries, the ink is thickened. When the ink inside the cavity is thickened, a discharge failure is caused. In addition, when air bubbles are included in the ink inside the cavity, or when paper powder is attached to a nozzle that discharges the ink, discharge failure is caused. Accordingly, it is preferable to inspect a discharge state of the ink.
In JP-A-2004-276544, a vibration is given to the ink inside the cavity by using a piezoelectric element, and a behavior of the ink is detected with respect to a residual vibration thereof. Accordingly, a technique is disclosed that determines the discharge state.
Meanwhile, in a case where the discharge state of the ink is inspected during printing, if the ink is discharged by the vibration given to the piezoelectric element, a recording medium is stained. Furthermore, ink is consumed. For this reason, it is preferable to drive the piezoelectric element such that the ink is not discharged during the inspection. In order to drive the piezoelectric element such that the ink is not discharged, an inspection pulse having a small amplitude may be applied to the piezoelectric element.
However, there is a problem that an excitation force given to the ink is small and the residual vibration cannot be accurately detected with the inspection pulse having a small amplitude.